gnome3.seahorse: clean up

pkgs/desktops/gnome-3/apps/seahorse/default.nix

@@ -4,37 +4,36 @@
 , gnome3, librsvg, gdk_pixbuf, gpgme
 , libsecret, avahi, p11-kit, openssh }:
 
-stdenv.mkDerivation rec {
-  name = "seahorse-${version}";
+let
+  pname = "seahorse";
   version = "3.20.0";
+in stdenv.mkDerivation rec {
+  name = "${pname}-${version}";
 
   src = fetchurl {
-    url = "mirror://gnome/sources/seahorse/${gnome3.versionBranch version}/${name}.tar.xz";
+    url = "mirror://gnome/sources/${pname}/${gnome3.versionBranch version}/${name}.tar.xz";
     sha256 = "e2b07461ed54a8333e5628e9b8e517ec2b731068377bf376570aad998274c6df";
   };
 
-  passthru = {
-    updateScript = gnome3.updateScript { packageName = "seahorse"; attrPath = "gnome3.seahorse"; };
-  };
-
   doCheck = true;
 
-  propagatedUserEnvPkgs = [ gnome3.gnome-themes-standard ];
-
   NIX_CFLAGS_COMPILE = "-I${gnome3.glib.dev}/include/gio-unix-2.0";
 
-  nativeBuildInputs = [ pkgconfig ];
-  buildInputs = [ gtk3 glib intltool itstool gnome3.gcr
-                  gnome3.gsettings-desktop-schemas wrapGAppsHook gnupg
-                  gdk_pixbuf gnome3.defaultIconTheme librsvg gpgme
-                  libsecret avahi libsoup p11-kit vala
-                  openssh ];
+  nativeBuildInputs = [ pkgconfig vala intltool itstool wrapGAppsHook ];
+  buildInputs = [
+    gtk3 glib gnome3.gcr
+    gnome3.gsettings-desktop-schemas gnupg
+    gnome3.defaultIconTheme gpgme
+    libsecret avahi libsoup p11-kit
+    openssh
+  ];
 
-  preFixup = ''
-    gappsWrapperArgs+=(
-      --prefix XDG_DATA_DIRS : "${gnome3.gnome-themes-standard}/share"
-    )
-  '';
+  passthru = {
+    updateScript = gnome3.updateScript {
+      packageName = pname;
+      attrPath = "gnome3.${pname}";
+    };
+  };
 
   meta = with stdenv.lib; {
     homepage = https://wiki.gnome.org/Apps/Seahorse;